1. Field of the Invention
The present invention relates to technology for delivering keys used in decrypting encrypted contents.
2. Related Art
In recent years, copyright protection of digitalized content such as movies, music, game computer programs and so forth has been sought, and the management of the digitalized content has become an important issue.
Unexamined Japanese patent application 2000-357213 discloses technology effective in content management that aims to protect copyright by regulating the number of duplications of a content. With this method, a recording apparatus that is to duplicate a content onto a recording medium while regulating the number of duplications of the content that can be recorded onto the recording medium, conducts mutual authentication with the recording medium, and if authentication is successful, the recording apparatus manages content usage by duplicating the content to the recording medium or deleting the content.
However, with the above method, although the recording apparatus continually manages the use of contents duplicated to an apparatus connected to a network, the management of the contents duplicated to a recording medium is only possible when connected to the recording medium. For this reason, the possibility exists, for example, of the contents duplicated to a recording medium being improperly used by a third party.